新型球状Ni/Co-MOFs电极材料的构筑及电化学性能研究

金属有机框架(Metal-organic frameworks,MOFs)材料作为一种电化学活性材料受到了人们的广泛关注。本工作利用简单的一锅法以1,3,5-苯三甲酸(H_(3)BTC)为有机配体、六水合氯化镍(NiCl_(2)·6H_(2)O)和六水合硝酸钴(Co(NO_(3))_(2)·6H_(2)O)为金属离子中心来源,通过简单的一步溶剂热法构筑镍/钴金属有机框架材料(Ni/Co-MOFs)。通过扫描电子显微镜(SEM)、粉末X射线衍射仪(XRD)、X射线光电子能谱(XPS)和Brunauer-Emmett-Teller(BET)法等对Ni/Co-MOFs样品的微观形貌、结构组成进行了表征,并采用循环伏安、恒流充放电和电化学阻抗法测试了制备的Ni/Co-MOFs电极材料的电化学性能。结果表明,新型球状Ni/Co-MOFs被成功地构筑。室温下,在6 mol/L KOH电解质中,恒定电流密度为0.5 A/g时,Ni/Co-MOFs电极材料的比电容为779 F/g;当电流密度增大至5 A/g时,Ni/Co-MOFs能够保持初始电容的79%。此外,以Ni/Co-MOFs为正极、活性炭(AC)为负极组装了非对称超级电容器,Ni/Co-MOFs‖AC非对称超级电容器器件在电流密度为0.5 A/g时的比电容为107 F/g,在功率密度为400 W/kg时的能量密度为38 Wh/kg,经过10000次连续的充放电循环后,该器件能够保留初始比电容的65.71%。上述研究结果表明,所制备的Ni/Co-MOFs在储能器件领域具有潜在的应用价值。

Ni/Co-MOF的制备及对酸性橙156的吸附

文章采用溶剂热法制备得到一种新型复合材料Ni/Co-MOF,并对其进行表观形貌、结构表征及对酸性染料吸附性能的研究。结果表明,Ni/Co-MOF具有独特的花瓣状中空纳米笼结构,孔径高达14.56 nm;Ni/Co-MOF对酸性橙156的吸附量最高可达355mg/g;通过吸附等温线和动力学研究说明酸性橙156在Ni/Co-MOF上的吸附符合Langmuir等温线模型和准二级动力学模型,为吸热自发过程,吸附方式以化学吸附为主;5次吸附与脱附试验后,Ni/Co-MOF仍可对酸性橙156表现出优异的吸附性能。

碳布表面Ni/Co-MOF阵列生长及其电化学性能

以活性碳布(CC)作为导电基底材料,采用水热法在其表面生长分层片状双配体Ni/Co-MOF[Ni/Co(PTA)_(2)(2-MI)_(2)]阵列,得到Ni/Co-MOF@CC复合电极材料。探究Co^(2+)含量对Ni/Co-MOF形貌的影响,利用SEM、XRD和TEM对复合电极进行结构表征,并对其进行电化学性能测试。结果表明:在Co^(2+)含量为1.5 mmol时,Ni/Co-MOF阵列以分层片状均匀地生长于碳布表面;该条件下获得的Ni/Co-MOF@CC复合电极在电流密度为2 mA/cm^(2)时比电容可达745.5 F/g,且循环5000次后比电容保持率达到88.2%。该研究为开发性能优异的超级电容器电极材料提供了新思路。

基于Co-MOF/GN复合材料构建的电化学传感器检测CA125的研究分析

论文采用室温合成法首先设计了带有介孔结构的Co-MOF/GN复合材料。使用扫描电镜(SEM)对Co-MOF结构进行了表征。同时利用循环伏安法(CV)、差分脉冲伏安法(DPV)等电化学方法,对Co-MOF/GN复合材料进行了电化学性能的分析及探讨。基于Co-MOF/GN复合材料构建的电化学传感器应用于肿瘤标志物CA125的分析检测,检测灵敏度良好,有望应用于临床分析检测。

Co基金属有机框架及其衍生材料的电催化析氢研究进展

电催化裂解水产氢是一种可持续的环保能源储存技术,也是降低碳排放的重要手段。金属有机框架(MOFs)因具有比表面积大、孔隙率可调、结构调整多样化及修饰策略简易等优点,从而在电催化析氢领域引起了研究者的广泛关注。综述了Co基金属有机框架(Co-MOFs)及其衍生材料的制备方法、结构调节,以及微观结构对催化活性、催化稳定性和析氢能力的影响。结果表明:Co-MOFs及其衍生材料较传统催化剂表现出更加优异的电化学析氢活性。此外,提出了高性能催化剂的设计策略,并对其在电催化析氢领域的应用前景进行了展望。

Efficient adsorption separation of methane from C_(2)-C_(3) hydrocarbons in a Co(Ⅱ)-nodes metal-organic framework

Methane(CH_(4))as a substitute for other mineral fuels plays a crucial role in reducing energy consumption and preventing environmental pollution.The present study employs a solvothermal method to fabricate a porous framework Co-metal-organic framework(Co-MOF)containing two distinct secondary building units(SBUs):an anionic[Co_(2)(μ_(2)-OH)(COO)_(4)(H_(2)O)]and a neutral[CoN_(2)(COO)_(2)].Notably,within the anionic SBUs,the coordinated water molecules induce the generation of divergent unsaturated Co(Ⅱ)centers in the unidirectional porous channels,thereby creating open metal sites.The adsorption performance of Co-MOF towards pure component gases was systematically investigated.The results demonstrated that Co-MOF exhibits superior adsorption capacity for C_(2)-C_(3) hydrocarbons compared to CH_(4),which offers the potential for efficient adsorption and separation of CH_(4) from C_(2)-C_(3) hydrocarbons.The gas selectivity separation ratios of Co-MOF for C_(2)H_(6)/CH_(4) and C_(3)H_8/CH_(4) were calculated using the ideal adsorbed solution theory method at 273/298 K and 0.1 MPa.The results revealed that Co-MOF achieved remarkable equilibrium separation selectivity for CH_(4) and C_(2)-C_(3) hydrocarbon gases among non-modified MOFs,signifying the potential of the synthesized Co-MOF for efficient recovery and purification of CH_(4) from C_(2)-C_(3) hydrocarbons.Breakthrough experiments further demonstrate the ability of Co-MOF to purify methane from C_(2)-C_(3) hydrocarbons in practical gas separation scenarios.Additionally,molecular simulation calculations further substantiate the propensity of anionic SBUs to interact with C_(2)-C_(3) hydrocarbon compounds.This study provides a novel paradigm for the development of porous MOF materials in the application of gas mixture separation.

基于硫化钼及金属有机骨架材料Co-MOF的5-羟色胺电化学传感器的研制

5-羟色胺(5-HT)是人体中枢神经系统的重要神经递质,其含量及功能异常与重度抑郁和自杀行为等多种疾病的发病有关。本文采用AuNPs@MoS2@金属有机骨架材料(Co-MOF)复合材料修饰电极,构建高灵敏、特异性强的电化学传感器检测5-羟色胺(5-HT)。实验考察了测试底液、pH、富集电压及时间对传感器响应电流的影响,结果表明在pH为7.0的PBS溶液中,富集电压为-0.1V条件下,该传感器响应性能最佳,线性范围为1μmol·L^(-1)~100μmol·L^(-1),检测下限为0.5μmol·L^(-1),该传感器具有稳定性好,制作简单,使用寿命长等特点,为实际样品中5-羟色胺的测定提供了一种新的简便手段。

载钯双金属Cu/Co-MOF的制备及催化降解方面的应用

金属框架材料(MOFs)具有高比表面积、高孔隙率、可重复利用等优点,近年来作为吸附剂在处理染料废水方面得到广泛应用。将2-甲基咪唑同硝酸铜和硝酸钴溶液在室温下按一定比例进行反应合成双金属Cu/Co-MOF,采用硼氢化钠还原将Pd负载在Cu/Co-MOF上,得到分散性能良好的Pd@Cu/Co-MOF颗粒。通过场发射扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)、X射线衍射仪(XRD)等测试手段对双金属Cu/Co-MOF材料的形貌、结构、组成进行表征。以胭脂红和硼氢化钠这一还原反应为模型,采用紫外-可见分光光度计(UV-Vis)来观察Pd@Cu/Co-MOF颗粒的催化降解性能。结果表明:制得的Pd@Cu/Co-MOF纳米颗粒具有良好的催化降解胭脂红染料的效能,且该催化剂能够多次循环使用,容易大量制备。

Co-MOF as an electron donor for promoting visible-light photoactivities of g-C3N4 nanosheets for CO2 reduction

A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.

Enhancement effect of Mn doping on Co_(3)O_(4)derived from Co-MOF for toluene catalytic oxidation

The design of Co-Mn composite oxides catalysts derived from MOF is significant for catalytic combustion of toluene.Here,a series of M-CoaMnfbOx,with enhanced catalytic properties compared with that of MCo_(3)O_(4),were successfully prepared through pyrolysis of Mn-doped Co-MOF.The as-synthesized MCo1Mn1Ox(Co:Mn=1:1)exhibits an optimal catalytic activity with 90%toluene conversion reached at227℃,which benefits from the increase of Co^(3+),Oadsand the synergistic effect between Mn and Co.According to the analysis of the in situ diffuse reflectance infrared Fourier transform spectroscopy,toluene could be degraded easier on M-Co1Mn1Oxwith lower activation energy than M-Co_(3)O_(4).The main intermediate products are benzaldehyde,benzoic acid,anhydride,and maleate species.Those findings reveal the value of Mn doping for improved activity of toluene oxidation on MOF derived Co_(3)O_(4),which provide a feasible method for the construction of toluene-oxidation catalysts.

Enhanced photocatalytic hydrogen production from Co-MOF/CN by nitrogen and sulfur co-doped coal-based carbon quantum dots

A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

Developing lightweight and broadband microwave absorbers for dealing with serious electromagnetic radiation pollution is a great challenge.Here,a novel Fe-Co/N-doped carbon/reduced graphene oxide(Fe-Co/NC/rGO)composite with hierarchically porous structure was designed and synthetized by in situ growth of Fe-doped Cobased metal organic frameworks(Co-MOF)on the sheets of porous cocoon-like rGO followed by calcination.The Fe-Co/NC composites are homogeneously distributed on the sheets of porous rGO.The Fe-Co/NC/rGO composite with multiple components(Fe/Co/NC/rGO)causes magnetic loss,dielectric loss,resistance loss,interfacial polarization,and good impedance matching.The hierarchically porous structure of the Fe-Co/NC/rGO enhances the multiple reflections and scattering of microwaves.Compared with the Co/NC and Fe-Co/NC,the hierarchically porous Fe-Co/NC/rGO composite exhibits much better microwave absorption performances due to the rational composition and porous structural design.Its minimum reflection loss(RLmin)reaches?43.26 dB at 11.28 GHz with a thickness of 2.5 mm,and the effective absorption frequency(RL≤?10 dB)is up to 9.12 GHz(8.88-18 GHz)with the same thickness of 2.5 mm.Moreover,the widest effective bandwidth of 9.29 GHz occurs at a thickness of 2.63 mm.This work provides a lightweight and broadband microwave absorbing material while offering a new idea to design excellent microwave absorbers with multicomponent and hierarchically porous structures.

Synthesis of Mn/Co-MOF for effective removal of U(VI) from aqueous solution

Ultrasound-assisted synthesis of Mn/Co-MOF nanomaterial was used to capture uranium from aqueous solutions. Tests of Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectra (FT-IR), Zeta potential analysis, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) suggest that cobalt ions were replaced partially by manganese ions to generate MOF during the synthesis process and form manganous oxide particles loaded on the surface of Mn/Co-MOF. The optimal immobilization conditions of U(VI) were systematically studied by solution pH, kinetic, contact time and preparatory uranium concentration. XPS spectroscopy analysis indicated that the chelation of imidazole ring to uranium and Mn3O4 possibly played a certain role in the adsorption process. The results indicate that the adsorption isotherms of the Mn/Co-MOF for uranium suit Langmuir isotherm model (maximum adsorption capacity were 763.36 mg/g). Furthermore, the adsorption kinetics of Mn/Co-MOF match comfortably with the pseudo-second-order kinetic model.

Boosting charge separation of BiVO_(4)photoanode modified with 2D metal-organic frameworks nanosheets for high-performance photoelectrochemical water splitting

Water splitting by photoelectrochemical(PEC)processes to convert solar energy into hydrogen energy using semiconductors is regarded as one of the most ideal methods to solve the current energy crisis and has attracted widespread attention.Herein,Co-based metal-organic framework(Co(bpdc)(H_(2)O)_(4)(CoMOF)nanosheets as passivation layers were in-situ constructed on the surface of Bi VO_(4)films through an uncomplicated hydrothermal method(Co-MOF/Bi VO_(4)).Under AM 1.5G illumination,synthesized CoMOF/BiVO_(4)electrode exhibited a 4-fold higher photocurrent than bare Bi VO_(4),measuring 6.0 m A/cm^(2)at 1.23 V vs.RHE in 1 mol/L potassium borate electrolyte(pH 9.5)solution.Moreover,the Co-MOF/BiVO_(4)film demonstrated a 96%charge separation efficiency,a result caused by an inhibited recombination rate of photogenerated electrons and holes by the addition of Co-MOF nanosheets.This work provides an idea for depositing inexpensive 2D Co-MOF nanosheets on the photoanode as an excellent passivation layer for solar fuel production.

Activation of sulfite by metal-organic framework-derived cobalt nanoparticles for organic pollutants removal

Sulfite(SO_(3)^(2−))activation is one of the most potential sulfate-radical-based advanced oxidation processes,and the catalysts with high efficiency and low-cost are greatly desired.In this study,the cobalt nanoparticles embedded in nitrogen-doped graphite layers(Co@NC),were used to activate SO32−for removal of Methyl Orange in aqueous solution.The Co@NC catalysts were synthesized via pyrolysis of Co^(2+)-based metal-organic framework(Co-MOF),where CoO was firstly formed at 400℃ and then partially reduced to Co nanoparticles embedded in carbon layers at 800℃.The Co@NC catalysts were more active than other cobaltbased catalysts such as Co^(2+),Co_(3)O_(4) and CoFe_(2)O_(4),due to the synergistic effect of metallic Co and CoxOy.A series of chain reaction between Co species and dissolved oxygen was established,with the production and transformation of SO_(3)•−,SO_(5)^(2−),and subsequent active radicals SO_(4)•−and HO•.In addition,HCO_(3)−was found to play a key role in the reaction by complexing with Co species on the surface of the catalysts.The results provide a new promising strategy by using the Co@NC catalyst for SO3_(2)−oxidation to promote organic pollutants degradation.

Metal-organic framework-derived, Zn-doped porous carbon polyhedra with enhanced activity as bifunctional catalysts for rechargeable zinc-air batteries

Zinc-air batteries have recently attracted considerable interest owing to the larger storage capacity and lower cost compared to their lithium-ion counterparts. Electrode catalysts for the oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） play a critical role in the operation of rechargeable zinc-air batteries. Herein, we report a simple and scalable strategy to fabricate porous carbon polyhedra using Zn-doped Co-based zeolitic imidazolate frameworks （ZnCo-ZIFs） as precursors. Strikingly, Zn doping leads to smaller Co nanoparticles and higher nitrogen content, which in turn enhances the ORR and OER activities of the obtained porous carbon polyhedra. The synergistic effect of the N-doped carbon and cobalt nanoparticles in the composite, the improved conductivity resulting from the high graphitization of carbon, and the large surface area of the porous polyhedral structure resulted in porous carbon polyhedra with excellent ORR and OER electrocatalytic activity in alkaline media. More importantly, air cathodes based on the optimal porous carbon polyhedra further exhibited superior performance to Pt/C catalysts in primary and rechargeable zinc-air batteries.